The cheapest place that I found found to buy KT tape is here:
http://store.elitehfp.com/
I have also found that if you use the contact form on their site, they can pretty much give you advice on what to do for any kind of injury.

KT Tape is a revolutionary sports medicine solution for treating and preventing common sports injuries such as ITBS, shin splints, plantar fasciitis, knee pain and more. Ultra-light, elastic, and strong, KT Tape is highly effective at providing pain relief, stability & support, & faster recovery for injured or sore muscles and joints-without sacrificing comfort or freedom of movement.

How does it work?

KT Tape is applied along muscles, ligaments, and tendons (soft tissue) to provide a lightweight, strong, external support that helps to prevent injury and speed recovery. KT Tape works differently for different injuries. KT Tape can lift and support the knee cap, holding it in place for Runnerís Knee. KT Tape can support sagging muscles along the arch of the foot, relieving the connective tissues for Plantarís Fasciitis. And KT Tape can lift the stress off of shin splints to allow pain release and give the body a better opportunity to recover. Depending on how it is applied, KT Tape supports, enables, or restricts soft tissue and its movement. By stretching and recoiling like a rubber band, KT Tape augments tissue function and distributes loads away from inflamed or damaged muscles and tendons, thereby protecting tissues from further injury.

By applying KT Tape over affected tissue, athletes experience an external support which helps to prevent further injury and allows the bodyís damaged tissue to rest and heal naturally despite continued activity. KT Tape also reduces inflammation and increases circulation which prevents muscle cramping and lactic acid buildup.

Itís designed for Professional athletes, Olympians, and active people world-wide who take health & fitness seriously and who refuse to stop training, playing, or living life active and free. The design is minimalist, the results are magic.provides relief and support for muscles and joints and can be used to prevent or treat hundreds of sports injuries.